Data transmitting apparatus, data sharing system, data sharing method, and message exchange system

摘要

A data transmission device that transmits data to another node, the data transmission device including: data storing unit for storing data; summary information storing unit for classifying data stored in the data storing unit into prescribed groups and for storing summary information that represents the number of pieces of data for each group; receiving unit for receiving summary information from the other node; selecting unit for selecting data to be transmitted based on the summary information received from the other node; and transmitting unit for transmitting the data selected by the selecting unit. The selecting unit favorably preferentially selects data included in a group with a smaller number of pieces of data based on the summary information received from the other node. Due to such a configuration, information with a high possibility of not being possessed by a communication partner can be selected and transmitted in a data sharing system.